Last year we had the coldest December in more than a century, with repeated heavy snowfalls and prolonged sub-zero temperatures.

This year has been a starkly different story, with conditions so far this month being much more normal for the time of year.

The huge difference from one year to the next is shown in the satellite images from NERC Satellite Receiving Station, Dundee University, Scotland. In 2010 the UK was blanketed with snow and ice, whereas this year only areas of high ground in Scotland, the Lake District and the Pennines show traces of white.

The UK covered in snow 24 December 2010

Relatively snow free UK 18 December 2011

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The main reason for the difference is down to the weather patterns seen last December compared to this year.

In December 2010 a high pressure system was sitting over the UK, blocking the normal westerly flow from the Atlantic and allowing easterly winds to bring in cold air from the continent.

This year, the mild westerly has been unimpeded – allowing milder Atlantic air and changeable, often stormy, conditions to take charge.

December 2010 was the coldest on record for the UK, with temperatures 5 °C below the long term average, with -21.3 °C being recorded in Altnaharra in Scotland on 2 December. There were also 23 days of frost, 13 more than the average.

Temperatures so far this December have been notable only for being so average. UK mean temperatures for the first half of the month were spot on the long term average of 6.9 °C. The lowest temperature recorded so far this December is -9.4 °C, recorded at Loch Glascarnoch in Scotland on 18 December.

1 -31 December 2010 mean temperature

1-14 December 2011 mean temperature

The reason for these stark differences from one year to the next is down to natural variability in our weather – something we Brits are well used to and why we expect to see differences in our weather from one year to the next and even one day to another.
However, the challenge of forecasting our variable weather is something the Met Office rises to every day and explains why we are regularly ranked in the top two national weather services in the world.

We are also continuing our improve our expertise through scientific research to look at how certain cycles or indicators in global climate, such as El Niño, work together to drive weather patterns over the UK.

To keep up to date with what we’re expecting for the rest 2011 and into 2012, you can check our forecasts which look out to 30 days ahead.